Many types of pressure vessels are known, such as for tanker trucks, LPG tanker ships, spacecraft propellant tanks, fire extinguishers and many others. With the exception of some designs of spacecraft propellant tanks, virtually all are constructed having a cylindrical body, with a concave or convex cap or bulkhead at each end. In some designs, the bulkhead may be flat, although this design is inherently the most structurally inefficient and requires heavier and thicker bulkheads than concave or convex bulkheads. Typically, conical, hemispherical and elliptical bulkheads are used, although for upright applications additional structure is required to maintain a vertical orientation.
With respect to liquid-fueled spacecraft, typical designs, such as found in the Space Shuttle, and referring to the prior art drawings of FIGS. 1, 1a incorporate fuel and oxidizer tanks having either round or cylindrical bodies, with bulkheads of adjacent ends of tanks being either of rounded or elliptical configurations. While these rounded or elliptical configurations are strong and allow for lighter tanks, rounded and elliptical configurations for such bulkheads are inefficient with respect to volume in adjacent bulkhead areas, and allow for a relatively large vortex to form when fuel is drawn from a natural low point in the bulkhead. Development of such a large vortex requires maintenance of a relatively large fuel residual to be left in the tank to avoid gas or vapor from being drawn into one or more engines of the spacecraft.
In some designs that have been considered, a common bulkhead is used between oxidizer and propellant tank sections. However, in these designs it is usually necessary to route fuel tubing from an upper tank through a lower tank to a rocket engine. This creates manufacturing problems due to the necessity that tanks and interior tubing be fabricated integrally. In addition, if a defect is found in one tank section then the entire assembly must be scrapped or reworked. Further, common or nested bulkhead tank systems do not lend themselves well to fabrication methods where there is an assembly-line type procedure for fabrication of a number of identical oxidizer and propellant tanks, such as found in the Space Shuttle program,
In accordance with the foregoing, Applicant proposes asymmetrical tank bulkhead designs that overcome the aforementioned problems, as will become apparent from a reading of the following specification.